Left-Handed DNA in Synthetic and Topologically Constrained Form V-DNA

We have investigated structural transitions in Poly(dG-dC) and Poly(dG-Me5dC) in order to understand the exact role of cations in stabilizing left-handed helical structures in specific sequences andthe biological role, if any, of these structures. From a novel temperature dependent transition it has been shown that a minor fluctuation in Na+ concentration at ambient temperature can bring about Β to Ζ transition. Forthe first time, wehave observed a novel double transition in poly(dG-Me5dC) as the Na+ concentration is gradually increased. This suggests that a minor fluctuation in Na+ concentration in conjunction with methylation may transform small stretches of CG sequences from one conformational state to another. These stretches could probably serve as sites for regulation. Supercoiled formV DNA reconstituted from pBR322 and pßG plasmids have been studied as model systems, in order to understand the nature and role of left-handed helical conformation in natural sequences. A large portion of DNA in form V, obtained by reannealing the two complementary singlestranded circles is forced to adopt left-handed double helical structure due to topological constraints (Lk = 0). Binding studies with Z-DNA specific antibody and spectroscopic studies confirm the presence of left-handed Z-structure in the pßG and pßR322 form V DNA. Cobalt hexamine chloride, which induces Z-form in Poly(dG-dC) stabilizes the Z-conformation in form V DNA even in the non-alternating purine-pyrimidine sequences. A reverse effect is observed with ethidium bromide. Interestingly, both topoisomerase I and II (from wheat germ) act effectively on form V DNA to give rise to a species having an electrophoretic mobility on agarose gel similar to that of open circular (form II) DNA. Whether this molecule is formed as a result of the left-handed helical segments of form V DNA undergoing a transition to the right-handed B-form during the topoisomerase action remains to be solved.

Fluidity of mica particle dispersed aluminium alloy

Cast aluminium alloy-mica particle composites were made by dispersing mica particles in a vortex produced by stirring the liquid Al-4 wt% Cu-1.5 wt% Mg alloy and then casting the melt containing the suspended particles into permanent moulds. Spiral fluidity and casting fluidity of the alloy containing mica particles in suspension were determined. Both the spiral fluidity and the casting fluidity of the base alloy were found to decrease with an increase in volume or weight percent of mica particles (of a given size), and with a decrease in particle size (for a given amount of particles). The fluidities of Al-4 wt% Cu-1.5 wt% Mg alloys containing suspended mica particles were found to correlate very well with the surface area of suspended mica particles. The regression equation for spiral fluidity Y (cm) as a function of surface area of mica particles per gram of spiral X (cm2 g–1) at 700° C was found to be Y=42.62–0.42X with a correlation coefficient of 0.9634. The regression equations for casting fluidity Yprime (cm) as a functiono of surface area of mica particles per gram of fluidity test piece Xprime (cm2 g–1) at 710 and 670° C were found to be Yprime=19.71–0.17Xprime and Yprime=13.52–0.105Xprime with correlation coefficients of 0.9194 and 0.9612 respectively. The percentage decrease in casting fluidity of composite melts containing up to 2.5 wt% mica with a drop in temperature is quite similar to the corresponding decrease in the casting fluidity of base alloy melts (without mica). The change in fluidity due to mica dispersions has been discussed in terms of changes in viscosity of the composite melts. However, the fluidities of these composite alloys containing up to 2.5 wt% mica are adequate for making a variety of simple castings including bearings for which these alloys have been developed.

x-ray studies on crystalline complexes involving amino-acids and peptides .10. head-to-tail sequences in the crystal-structure of l-lysine acetate

l-Lysine acetate crystallises in the monoclinic space group P21 with a = 5.411 (1), b = 7.562(1), c= l2.635(2) Å and β = 91.7(1). The crystal structure was solved by direct methods and refined to an R value of 0.049 using the full matrix least squares method. The conformation and the aggregation of lysine molecules in the structure are similar to those found in the crystal structure of l-lysine l-aspartate. A conspicuous similarity between the crystal structures of l-arginine acetate and l-lysine acetate is that in both cases the strongly basic side chain, although having the largest pK value, interacts with the weakly acidic acetate group leaving the α-amino and the α-carboxylate groups to take part in head-to-tail sequences. These structures thus indicate that electrostatic effects are strongly modulated by other factors so as to give rise to head-to-tail sequences which have earlier been shown to be an almost universal feature of amino acid aggregation in the solid state.

Twitter hashtags from ad hoc to calculated publics

As the use of Twitter has become more commonplace throughout many nations, its role in political discussion has also increased. This has been evident in contexts ranging from general political discussion through local, state, and national elections (such as in the 2010 Australian elections) to protests and other activist mobilisation (for example in the current uprisings in Tunisia, Egypt, and Yemen, as well as in the controversy around Wikileaks). Research into the use of Twitter in such political contexts has also developed rapidly, aided by substantial advancements in quantitative and qualitative methodologies for capturing, processing, analysing, and visualising Twitter updates by large groups of users. Recent work has especially highlighted the role of the Twitter hashtag – a short keyword, prefixed with the hash symbol ‘#’ – as a means of coordinating a distributed discussion between more or less large groups of users, who do not need to be connected through existing ‘follower’ networks. Twitter hashtags – such as ‘#ausvotes’ for the 2010 Australian elections, ‘#londonriots’ for the coordination of information and political debates around the recent unrest in London, or ‘#wikileaks’ for the controversy around Wikileaks thus aid the formation of ad hoc publics around specific themes and topics. They emerge from within the Twitter community – sometimes as a result of pre-planning or quickly reached consensus, sometimes through protracted debate about what the appropriate hashtag for an event or topic should be (which may also lead to the formation of competing publics using different hashtags). Drawing on innovative methodologies for the study of Twitter content, this paper examines the use of hashtags in political debate in the context of a number of major case studies.

#auspol: The hashtag as community, event, and material object for engaging with Australian politics

Critical, loud, highly discursive and polarised; the #auspol hashtag represents a space, an event and a network for politically involved individuals to engage in and with Australian politics and speak to, at and about a variety of involved stakeholders. Contributors declare, debate and often berate each other’s opinions about current Australian politics. The hashtag itself is an important material object and engagement event involved within this performance of political participation. As a long-standing institution in the Twittersphere, and one studied by the authors and their colleagues since its early beginnings (Bruns and Burgess, 2011; Bruns and Stieglitz, 2012; 2013), the #auspol hashtag provides a potent case study through which to explore the discursive and affective dimensions of a hashtag public. This chapter that engages both empirically and theoretically with the use of this particular hashtag on Twitter to provide a qualitatively illustrated case in point for thinking about the long-term use of political hashtags as engagement events.

Short-lived triplets of aliphatic thioketenes

The photophysical behavior of the triplets of three aliphatic thioketenes, namely di-tert-butylthioketene (1), 2,6-di-tert-butylcyclohexylthioketene (2) and 2,2,6,6-tetramethylcyclohexylthioketene, has been studied in fluid solutions at room temperature by nanosecond laser flash photolysis. Upon 532 nm laser excitation into the S1 state, the thioketenes in concentrated benzene solutions produce very short-lived transient absorptions (τ < 5 ns; λmax ≈ 450 nm) attributable to their triplets. The photogeneration of the latter under S1 excitation has also been established by energy transfer to all-trans-1,6-diphenyl-1,3,5-hexatriene. The factors which render the triplet lifetimes short are shown to be intrinsic in origin (rather than self-quenching). Unlike thiocarbonyl compounds in general, the thioketenes posses low intersystem crossing yields (less than 0.1 in benzene). From the kinetics of the quenching of a series of sensitizer triplets by 1 and 2, the thioketene triplet energies are estimated to be 43 – 44 kcal mol−1.

Influence of heat treatment on the strength and fracture behaviour of Fe-12Cr-6Al ferritic stainless steel

The changes in the tensile properties and fracture mode brought about by heat treatment of Fe-12Cr-6Al ferritic stainless steel have been studied. A favourable combination of high strength and good ductility is obtained by heating the material at 1370 K for 2 h followed by a water quench. The high-temperature treatment results in carbide dissolution as well as an increase in the grain size. The mechanism of strengthening has been evaluated from the apparent activation energy (28 kJ mol–1) and is identified to be the unpinning of dislocations from the atmosphere of carbon atoms. As the heat-treatment temperature is increased, the fracture behaviour changes from ductile to brittle mode and this is related to the changes in grain size and friction stress.

A laser flash photolysis study of pivalothiophenone triplets: steric and electronic effects in thione photoreaction kinetics

Upon laser pulse excitation (Aex = 532 nm) into the lowest-lying '(n,a*) band system, pivalothiophenones in benzene solutions give rise to short-lived triplets (Ama: = 325-335 nm, em: = (1 1-15) X lo3 M-' cm-I) with quantitative intersystem crossing efficiencies. The triplet yields decrease slightly (by 10-30%) upon changing A, to 308 nm (Le., upon excitation into S2). Kinetic data are presented for intrinsic triplet lifetimes, self-quenching, and quenching by oxygen, di-tert-butylnitroxy radical, and various reagents capable of interacting with the triplets via energy, electron, or hydrogen-atom transfer and by biradical formation (possibly leading to cycloaddition). The mechanisms of the quenching processes are discussed. Relative to rigid aromatic thiones, namely, xanthione and thiocoumarin, the interaction of pivalothiophenone triplets with most of the quenchers are kinetically inefficient. This is interpreted primarily as a manifestation of the steric crowding at positions a to the thiocarbonyl group.

Kiinan kielen automaattinen käsittely ja kieliteknologia

Tutkielma käsittelee kiinan kielen automaattista käsittelyä ja kieliteknologiaa. Kieliteknologian osa-alueista keskitytään kiinan kielelle tyypilliseen sanarajatunnistus- eli segmentointiongelmaan, joka kumpuaa kiinan kielen kirjoitusjärjestelmän erityispiirteistä. Tutkielma on aihepiiriä esittelevä pilottitutkimus, jonka tarkoitettu lukijaryhmä on kiinan kieliteknologisesta tutkimuksesta kiinnostuneet opiskelijat ja tutkijat. Lähdemateriaali koostuu englannin- ja kiinankielisestä kirjallisuudesta, lähinnä konferenssiartikkeleista. Tutkielma esittelee kiinan kirjoitusjärjestelmää automaattisen käsittelyn näkökulmasta, käsittelee perinteisten ja yksinkertaistettujen merkkien eroja, merkkikoodauksia sekä erilaisia lähestymistapoja käyttäviä syöttöjärjestelmiä. Kirjoitusjärjestelmän esittely tarjoaa esitietoja kielen rakenteen ymmärtämiseksi sekä rakentaa pohjaa sanarajatunnistusta käsitteleviä osuuksia varten. Sanarajatunnistus- eli segmentointiongelma johtuu kiinan kirjoitusjärjestelmästä, jossa sanojen välejä ei merkitä välilyönneillä. Kielen kieliteknologista käsittelyä varten sanojen rajat tulee kuitenkin selvittää. Sanarajatunnistusjärjestelmät ovat tietokoneohjelmia, jotka etsivät ja merkitsevät nämä rajat automaattisesti. Tehtävä ei kuitenkaan ole yksinkertainen kielen monitulkintaisuuksien ja ns. tuntemattomien sanojen vuoksi. Joissain tilanteissa ei ole olemassa yksiselitteisen oikeaa segmentointia. Tutkielmassa esitellään kaksi segmentointijärjestelmää, keskittyen erityisesti niiden toiminnan kuvaukseen lukijalle ymmärrettävässä muodossa. Tärkeää on menetelmien ymmärtäminen, ei tekniset yksityiskohdat. Lopuksi paneudutaan segmentointijärjestelmien evaluaation ongelmiin. Sanarajatunnistusta suorittavien ohjelmien vertailu on usein hankalaa, koska monissa tapauksissa järjestelmät eivät tuota yhteismitallisia tuloksia. Tutkielmassa esitellään yritys saada aikaan yhteismitallisia evaluaatiomenetelmiä segmentointiohjelmien Chinese Word Segmentation Bakeoff -kilpailujen muodossa. Tutkielmassa todetaan sanarajatunnistusongelman olevan tärkeä tutkimuskohde. Ratkaisemattomia ongelmia on kuitenkin edelleen, tärkeimpänä evaluaatio. Avainsanat – Nyckelord – Keywords kiinan kieli, sanarajatunnistus, segmentointi,kirjoitusmerkit, merkkikoodaukset, kiinan syöttötavat

Relocating the American Dream : The America of the 1960s as Portrayed by the New Journalists Norman Mailer, Hunter S. Thompson, and Tom Wolfe

The concept of the American Dream was subject to a strong re-evaluation process in the 1960s, as counterculture became a prominent force in American society. A massive generation of young people, moved by the Vietnam War, the hippie movement, and psychedelic experimentation, created substantial social turbulence in their efforts to break out of conventional patterns and to create a new kind of society. This thesis outlines and analyses the concept of the American Dream in popular imagination through three works of new journalism. My primary data consists of Tom Wolfe’s The Electric Kool-Aid Acid Test (1967), Hunter S. Thompson’s Fear and Loathing in Las Vegas: A Savage Journey to the Heart of the American Dream (1971), and Norman Mailer’s Armies of the Night: History as a Novel, the Novel as History (1968). In defining the American Dream, I discuss the history of the concept as well as its manifestations in popular culture. Because of its elusive and amorphous nature, the concept of the American Dream can only be examined in cultural texts that portray the values, sentiments, and customs of a certain era. I have divided the analytical section of my thesis into three parts. In the first part I examine how the authors discuss the American society of their time in relation to ideology, capitalism, and the media. In the second part I focus on the Vietnam War and the controversy it creates in relation to the notions of freedom and patriotism. In the third part I discuss how the authors portray the countercultural visions of a better America that challenged the traditional interpretations of the American Dream. I also discuss the dark side of the new dream: the problems and disillusions that came with the effort to change the world. This thesis is an effort to trace the relocation of the American Dream in the context of the 1960s counterculture and new journalism. It hopes to provide a valuable addition to the cultural history of the sixties and to the effort of conceptualizing the American Dream.

Complicated Presence : The Unity of Being in Parmenides and Heidegger

The attempt to refer meaningful reality as a whole to a unifying ultimate principle - the quest for the unity of Being - was one of the basic tendencies of Western philosophy from its beginnings in ancient Greece up to Hegel's absolute idealism. However, the different trends of contemporary philosophy tend to regard such a speculative metaphysical quest for unity as obsolete. This study addresses this contemporary situation on the basis of the work of Martin Heidegger (1889-1976). Its methodological framework is Heidegger's phenomenological and hermeneutical approach to the history of philosophy. It seeks to understand, in terms of the metaphysical quest for unity, Heidegger's contrast between the first (Greek) beginning or "onset" (Anfang) of philosophy and another onset of thinking. This other onset is a possibility inherent in the contemporary situation in which, according to Heidegger, the metaphysical tradition has developed to its utmost limits and thereby come to an end. Part I is a detailed interpretation of the surviving fragments of the Poem of Parmenides of Elea (fl. c. 500 BC), an outstanding representative of the first philosophical beginning in Heidegger's sense. It is argued that the Poem is not a simple denial of apparent plurality and difference ("mortal acceptances," doxai) in favor of an extreme monism. Parmenides' point is rather to show in what sense the different instances of Being can be reduced to an absolute level of truth or evidence (aletheia), which is the unity of Being as such (to eon). What in prephilosophical human experience is accepted as being is referred to the source of its acceptability: intelligibility as such, the simple and undifferentiated presence to thinking that ultimately excludes unpresence and otherness. Part II interprets selected key texts from different stages in Heidegger's thinking in terms of the unity of Being. It argues that one aspect of Heidegger's sustained and gradually deepening philosophical quest was to think the unity of Being as singularity, as the instantaneous, context-specific, and differential unity of a temporally meaningful situation. In Being and Time (1927) Heidegger articulates the temporal situatedness of the human awareness of meaningful presence. His later work moves on to study the situational correlation between presence and the human awareness. Heidegger's "postmetaphysical" articulation seeks to show how presence becomes meaningful precisely as situated, in an event of differentiation from a multidimensional context of unpresence. In resigning itself to this irreducibly complicated and singular character of meaningful presence, philosophy also faces its own historically situated finitude. This resignation is an essential feature of Heidegger's "other onset" of thinking.

Chemical approach to aspirin hypersensitivity

Rabbits and guinea pigs were immunized with functionalized aspirin-protein conjugates prepared by coupling 5-N-Succinylamino aspirin to BSA and BGG using a water soluble carbodiimide (EDC). Two populations of antibodies, one specific to functionalized aspirin and the other exclusively specific to salicylic acid were detected. These antibodies were fractionated and separated on affinity polymers suitably prepared with 5-N-succinylamino salicylic acid and 5-N-succinylamino-2-ethoxy benzoic acid as the ligands. The isolated and purified antibodies were electrophoretically homogeneous. The physico chemical interactions between the antibodies and the respective haptens were studied by radio-immunoassay, equilibrium dialysis and fluorescence quenching techniques.

Fluorescent labelling of strychnine: A novel approach for recognition of strychnine binding sites on neuronal membrane

trychnine was coupled to fluorescein isothiocyanate to mark strychnine binding sites in spinal cord of rat. Specific binding of strychnine could be demonstrated in synaptosomal fraction. Addition of glycine to the strychninised membrane led to a decrease in fluorescence indicating same receptor loci.

Easy to build four-terminal AC bridge

A simple four-terminal AC bridge is described which can be used with germanium resistance thermometers down to 1 K. The special features of the bridge are its ease of fabrication and extremely low cost.